A laboratory animal such as a mouse or a rat is raised in an exclusive breeding container the environment in which is controlled. When an animal experiment is started, for observation of influences of dosage of a drug or poison, the weight of an animal is continuously measured. For this, a simple method in which an animal is taken out of the breeding container and put on a weighing scale and weighed has been adopted until now, however, this method gives, in addition to the aspects of labor and cost, risks of infection between an experimenter and an animal due to touching the animal by the experimenter and contact with hazardous substances, and a problem in which the animal is subjected to stress by contact with a human, and therefore, there is a demand for automating animal weight measurement.
In response to such demand, for example, in Patent Literatures 1 and 2, animal weight measurement is performed without touching an animal by using an apparatus arranged to have a breeding container automatically movable up and down on a weighing scale.